An effective maintenance program is vital to this kind of success. Berar these things in mind while you consider the following benefits of a CBM program in greater detail. The operation and maintenance of high valuable machines is very important in increasingly stiff global market and requires that it provides maximum return on investment with minimum maintenance costs.
Improving plant efficiency by implementation of latest techniques in maintenance can lead to significant savings with improvement in overall operating efficiency of plants. This project brings outs the importance of vibration analyzing in maintaining the machines. The vibration analysis can be simplified and make time saving by analyzing the FFT Fast Fourier transform or amplitude vs. By analyzing the spectrum we can estimate the cause of vibrations in the machine.
Randall Frequency Analysis. Braun, S, J. Academic press, London. Collacot R.
Wiley, New York. Mitchell, j. Penn well books, Tulsa. Natke, H. Springer Verlag, Berlin. Dalpiaz, G. Effectiveness and sensitivity of vibration processing Techniques for local fault detection in gears. Mechanical systems and signal processing 14 3 Rubbini, R. Application of the envelope a Wavelet transforms analyses for the diagnosis of incipient faults in ball bearings. Mechanical systems and signal processing, 15 2 , Requiang, Y. Approximately Entropy as a diagnostic tool for machine health monitoring.
Mechanical system and signal processing,, 21, Shibata, K. Fault diagnosis of rotating machinery through visualization of sound signal. Mechanical systems and signal processing, 14 2 Rehorn, A. Mechanical systems and signal processing, 20, IRD Mechanalysis manual for training. CSI manual for vibration analysis. Vibxpert manual for fault diagnosis. Balachandra Pattanaik, S. Reliability numbers by themselves will not motivate improvements, performance of two fault tolerant mechanisms dealing with repairable and non-repairable components that have failed.
Reliability principles are discussed which assist system improvement for reducing the high unreliability. CAN Controllers are used in automotive for fault tolerant embedded system. The existing reliability enhancement models are emphasizing various redundancy techniques both in hardware and software without focusing a formal way of recovery time minimization from the affected or degraded states in the automotive systems.
Bosch, CAN Specification 2. Farsi and M. Navet, F. Aysan, A. Thekkilakattil, R. Dobrin, S. Nolte, H. Hansson, L. Navet, Y. Song, F. Simonot-Lion, C. FlexRay Consortium. Billiton R. Michale short and Michael J. A study of Bandwidth Management in Computer Networks.
Bandwidth Management is a lot like economics, because the complexities of how it works are beyond simple logic. Internet "bandwidth" is not a spectrum; traffic streams are one bit at a time. Bandwidth on the internet can only be conceptualized over time, and the amount of time that you talk about can greatly change the user experience. Without bandwidth management, an user will not be able to handle all available bandwidth on the networks.
It will be impossible to differentiate between various network traffics, and it will also be difficult to control which user or application has priority on the network. Introduction to bandwidth. Douglas Comer , Computer Networks and Internets , p. Behrouz A. Forouzan, Data communications and networking, McGraw-Hill, 8. Douglas E. Upper Saddle River: Prentice Hall. The resultant concrete was tested for parameters like weight, compressive strength, slump and workability and compared with conventional plain cement concrete. It has been observed that the use of waste materials results in the formation of light weight concrete.
There is a considerable increase in the compressive strength of concrete when the coarse aggregates are fully or partially replaced with construction debris. However a minor reduction in workability of the concrete mix was observed. When the coarse aggregates were replaced with PVC scrap in small percentage by weight, the resultant concrete shows fair value of compressive strength and the workability.
But with the partial introduction of leather waste in place of sand in concrete, the concrete passed workability test but it failed completely in compressive strength test and gave almost zero strength. Uses of such waste materials will not only cut down the cost of construction, but will also contribute in safe disposal of waste materials. Apart from the environmental benefits, the addition of such wastes, also improves certain properties of resultant concrete. Gambhir, M. Prasanna Kumar. The algorithm described here relies on breaking the character into four equal parts and using one of the quarters for extraction.
The algorithm is deliberately kept away from all the complexities and the number of features to be extracted is also minimized so as to increase the efficiency and speed of recognition. The algorithm also describes a conflict resolution technique helpful in effectively utilizing the algorithm. Brown, T. Fay, and C. Suen, C. Nadal, R. Legault, T. Mai, and L. Mittchell and A. Cun, L. Bottou, Y.
Bengio, and P. Shi, Y. Fujisawa, T. Wakbayashi, and F. Teow and K. Decoste and B. Xu, A. Krzyzak, and C. Lee and D. Gader and M. Weideman, M. Manry, H. Yau, and W. II-Seok Oh and C. Yang, C. Suen, T. Bui, and P. Gao and X. Oliveira, R. Sabourin, F. Bortolozzi, and C. Chen, T. Bui, and A. Shafait, J. Keysers, and T. Page frame detection for marginal noise removal from scanned documents.
Document cleanup using page frame detection. Abul Hasnat, S. Murtoza Habib, Mumit Khan Tinku Acharya and Ajoy K. Ray Retrieved 12 May Nitin Adhav, Shilpa Agarwal. Wind technology has been started many years ago, as it is clean and free energy source worldwide. This paper discuss the most emerging renewable energy source, wind energy, which by means of power electronics is changing from being a minor energy source to be acting as an important power source in the energy system.
By that wind power is also getting an added value in the power system operation . Blaabjerg, Z. Chen, R. Teodorescu, F. Juan Manuel Carrasco, Jan T. Barakati, M. Inside Wind turbine fixed Vs. Variable james and james Science publishers ltd. Voltage Source-PWM inverter 7.
Power Electronics and Drives Version 2 : Dr. Zainal Salam, 4. Dujic, E. Levi, M. Grandi, G. Serra, A. Suhail A. John and Dr. Sharifian, R. Rahnavard, Y. Chitti Babu , K. Niiranen, S. Kanerva, and A. Nikolay N.
Original Research ARTICLE
Lopatkin, Maria I. Mohamayee Mohapatra, B. Dalessandro, U. Drofenik, S. Round and J. Lecture 25 prof. Dorin O. Rafael K. Abdul Rahiman Beig G. Marques, H. Pinheiro, H. Pinheiro and H. Neel Kamal, D. There is a large escalation of demand for fresh water because of the rapid industrial growth and explosion of population all over the world.
Thus, it has become pertinent to do further research in this field to improve the sea water desalination process. The separation of salts from seawater requires significant amounts of energy. When the energy is produced from fossil fuels, this approach can harm the environment, and as desalination requires significant energy, this in turn is costly. Therefore, there is a need to employ environmentally-friendly and affordable energy sources, specifically renewable energy, in order to desalinate seawater.
Renewable energy comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are naturally replenished. Renewable energy can be used for seawater desalination. Hybridization of PV with Thermoelectric modules can increase the overall efficiency of the solar energy conversion system by keeping the temperature constant within limits. This paper is an attempt to explore the efficient mean of water pumping through augmentation of thermoelectric conversion to increase overall efficiency of PV array for pump operation of sea water desalination.
The study of thermoelectric is done to illustrate its usefulness in hybrid model of PV and thermoelectric modules. Model of hybrid combination of Thermoelectric — PV array have been developed and simulation results are also presented in this paper. Case, E. Li1, Taewon Lee, Fang. Applied Power Electronics Conference and Exposition Hamrouni, M. Jraidi, A. Cherif, A. Wenham, S. Xiao, X. Gou and C. IEEE Chen, L A.
Rosendahl, T. Condra, J. Page s Garg , R. Othman , B. Discovering Frequent Patterns Mining Procedures. Finding frequent itemsets is computationally the most expensive step in association rule discovery. To address these issues we discuss popular techniques for finding frequent itemsets in efficient way. In this paper we provide the survey list of existing frequent itemsets mining techniques and its analysis. Agrawal, R. Imielinski, T. Very Large Data Bases, pp. Park, J. Chan, M. ACM, May Brin, S.
Motwani, R. Ullman, J. Dynamic itemset counting and implication rules for market basket data, In Proc. Han, J. Pei, J. Kumar, A. International Conference on , vol. Samundiswary, Ravi Ranjan Prasad. The IEEE IEEE Std El-Najjar, B. Jaumard, C. Pravin Kumar Barmashe and Rof.
Bliss, K. Foschini and M. Biglieri, R. Calderbank, T. Constantinides, A. Goldsmith, A. Paulraj, and H. Shiu, G. Foschini, M. Gans, and J. Padmavathi, M. Madhavi, N. The group signature setting has a group with copious members and one manager. Every member of the group has a different list of unique private keys which is distributed by TC to sign a document. The keys are immunable using quantum key distribution protocol which acquires the properties of quantum mechanics.
Bennett and G. Computers, Systems, and Signal Processing, pp. Wootters and W. Gisin, G. Ribordy, W. Tittel, and H. Imre, F. Bennett, F. Bessette, G. Brassard, L. Salvail, and J. Nielsen and I. Jan Camenisch, Markus Michels. A group signature scheme with improved efficiency.
In Proc. Shi Rong-Hua. Blundo and S. Cimato Eds. Springer-Verlag Berlin Heidelberg Camenisch and M. Efficient and generalized group signatures. Benenti, G. Casatti, and G. Strini, Principles of Quantum computation, vol. Hwang, K. Lee, and C. Utpal Bhattacharjeeand Pranab Das.
The Automotive Chassis
The paper demonstrates by corrupting the speech signal with additive white Gaussian noise in simulated environment. It has been observed that spectral subtraction plays an important role in reduction low power Gaussian noise whereas Kalman filter is efficient in reduction noise when noise power is high. Wiener filter improves the performance at all level of noise. No considerable performance improvement has been observed when spectral subtraction is combined with other two methods.
Anderson and J. Moore, Optimal Filtering, Prentice Hall, Lim and A. Fujimoto and Y. Xiaojia, S. Yang and W. Kleynhans and E. Reynolds, "Robust text-independent speaker identification using Gaussian mixture speaker models," Speech Communications, vol. Charulata Ingle. This paper represents two features of embedded system namely multithreading and semaphore in embedded linux.
By using this we can build our own embedded system using linux as the kernel and freely available open source. Christopher Hallinan Embedded Linux Primer 6. Mayank Patel. In this internet world all the things are on-line. So we created software called On-line java compiler. The main aim of this project we can easily to write a java program and compile it and debug in on-line.
The paper aims todescribe an online compiler which helps to reduce the problems of portability and storage space by making use of the concept of cloud computing. The ability to use different compilers allows a programmer to pick up the fastest or the most convenient tool to compile the code and remove the errors.
Moreover, a web-based application can be used remotely throughout any network connection and it is platform independent. Also, the trouble of installing the compiler on each computer is avoided. ICFN ' Second Internation execute the program and its instructions.
Fig 1 - Cloud Computing logical diagram al Conference. Grobauer, B. Walloschek, T. Stocker, E. Second International Conference. Fuzzy logic control strategy is applied to doubly fed induction generator DFIG. DFIG consists of a common wound rotor induction generator with slip ring and a back to back voltage source convertor. Fuzzy logic controller is applied to both grid side convertor GSC for dc link voltage control and rotor side convertor RSC for active and reactive power control. Coordinated control of the grid- and rotor side converters GSC and RSC, respectively is presented in the positive synchronous reference.
Conventional dq axis current control using voltage source converters for both the grid side and the rotor side of the DFIG are analyzed and simulated. Simulation results prove the excellent performance of fuzzy control unit as improving power quality and stability of wind turbine. Hu, Y. He, Lie Xu and B. Dimitrios, G. Giaourakis, N. Sheikholeslami, H.
The Automotive Chassis Volume 2 System Design (Elements) - PDF Free Download
Livani and M. Christina N. Papadimitriou and Nicholas A. Babypriya, N. Dibin Chandran, M Lydia. The control of the active and reactive power is done with a rotor current controller. The problem in using a PI controller is the tuning of gain and cross-coupling on DFIG parameters in the whole operating range. Simulation results are presented to validate the proposed controllers. Datta and V. Energy Convers. Chowdhury and S. Hopfensperger, D. Atkinson, and R. Power Applications, vol. Takahashi and T. IA, no. Abu-Rub, J. Guzinski, Z. Krzeminski, and H. Bim, and W. Kusiak et al. When these guidance systems are used for docking, the space between vehicle and platform is within the ADA maximum horizontal gap allowed for rail transit vehicles approximately 3 inches.
Stations served by these guided, low-floor vehicles will have slightly raised platforms about 11 to 14 inches high instead of the roughly 6-inch normal curb height to permit platform-to- floor, no-step, direct boarding and alighting. Guided vehicles, used in conjunction with stations having platforms at the same height as the vehicle floor, can be expected to have boarding and alighting times similar to those on heavy rail or on some LRT systems, or approximately 1 sec- ond per person less than the passenger service times for con- ventional buses shown in Table Besides reducing aver- age passenger service times, no-step, no-gap boarding and alighting can significantly reduce the time it takes for customers with disabilities or customers with children in strollers or prams to board and alight from BRT vehicles.
This, combined with wide aisles, can significantly reduce passenger service times for these customers and thus improve schedule reliability. The disadvantage of this approach usually used with left-hand doors to sup- port center-median platforms is an inability to service off- line stations that are not configured with high platforms and center platforms. This disadvantage could be overcome by having doors on both sides of vehicles and steps feeding some of them, but this would reduce seating capacity, and the sys- tem would suffer from increased dwell times at the off-line stations.
Photo 6-J shows the As shown in Photo 6-K, a wide, no-step aisle supports cir- culation and makes it easier to access the rear of long, artic- ulated vehicles. Photo 6-L illustrates no-step boarding and alighting, as enabled by precision docking through an optical guidance system. The bridges allow no-step, no-gap boarding and alighting, yielding the extremely low passenger service times char- acteristic of high-platform metro rail and some LRT sys- tems. The vehicles used in these applications combine the boarding and alighting ease and speed of low-floor, guided vehicles with the interior room and capacity of high-floor vehicles.
Wide, no-step aisle supports circulation and makes it easier to access rear of long, articulated vehicles. No-step boarding and alighting enabled by optical guidance system. Key Physical Features BRT Propulsion Systems BRT vehicle propulsion systems affect system perfor- mance, ride quality, environmental impacts including noise and air pollutant emissions , attractiveness to customers and non-customers, service reliability, overall costs, and finan- cial feasibility.
An increasing variety of propulsion systems is in use or under development, particularly for use in BRT vehicles, but there are four basic types of systems. The most prevalent propulsion system is the thermal or internal com- bustion engine, usually diesel cycle compression ignition driving a hydraulic-mechanical transmission. The second com- monly used propulsion system is the electric vehicle or trolley bus. Trolley buses normally use electric power collected from an overhead contact system trolley wires to power an on- board electric motor or motors.
These vehicles have full service capabilities when powered either by an independent thermal engine e. The fourth and arguably most complex type of vehicle propulsion is the hybrid thermal-electric the thermal part can be diesel, CNG, or gas turbine. By definition, hybrid vehi- cles have both thermal and electric propulsion capabilities, but they also have on-board energy storage capabilities.
The on-board energy storage is usually electric either a battery or ultra-capacitor , although mechanical systems using flywheels and hydraulic systems with compressed gas tanks have been tried with mixed success in the past. This on-board energy storage allows the thermal engine to be operated within its maximum fuel efficiency and mini- mum emissions range and also provides the highly peaked energy and power needed for acceleration away from stops. This reduces the stress on the engine and allows it to be smaller and lighter, significantly reducing air and noise emissions and fuel consumption.
The on-board energy storage takes advantage of regenerative braking to reduce fuel consump- tion and brake wear and tear. Internal Combustion Engines The most common propulsion plant, and the one that would be likely if a conventional bus is selected for a BRT application, is the internal combustion e. Power output is typically in the range of to gross horsepower; however, for articulated vehicles operating on hilly terrain, engines up to gross horsepower have been used.
After deductions for driving auxiliaries such as an alterna- tor and air-conditioning compressor and after friction losses through the drive train, the net horsepower delivered to the wheels can be substantially less than the gross horsepower output. The trend is for vehicles to require more withdrawal of power for the alternator as the quantity of electrical equip- ment e. CNG-fuelled internal combustion engines are used by many operators to reduce emissions.
CNG engines have significantly higher fuel consumption and costs and generally higher main- tenance costs because to date they feature spark ignition and are throttled as opposed to unthrottled compression ignition diesels. They also require costly special garaging, servicing, and fuelling facilities. There have been significant improvements in diesel engines over the last two decades in response to the need to reduce emissions.
These are de- scribed in more detail in Section Contemporary spark ignition CNG engines have low par- ticulate emissions and can be somewhat quieter than diesels, but have higher total weight. They also Photo 6-M. In the future, clean diesel engines using catalytic convert- ers enabled by low-sulphur fuels and either CNG spark igni- tion or diesel hybrids promise an almost complete elimination of emissions as a planning and project development issue.
At the same time, advances in CNG engines e.
- Species: A History of the Idea (Species and Systematics)?
- The Handy Dinosaur Answer Book, Second Edition.
- Volume-2 Issue-2 | International Journal of Innovative Technology and Exploring Engineering(TM);
- The Automotive Chassis Volume 2 System Design (Elements)?
- Museum Culture: Histories, Discourses, Spectacles!
All-Electric Trolley Buses The other common propulsion system that has been proven over many decades of operation is the fully electric trolley bus. It uses an electric power usually provided from overhead contact trolley wires to drive motors that can be reversed to brake the vehicle saving brake wear and tear and to regen- erate power for other vehicles that may be simultaneously accelerating. Unlike rail vehicles that have only one contact wire because the rails provide the ground, trolley buses col- lect power from two wires, one hot, one ground.
Although this approach was aestheti- cally superior to overhead cables, it was expensive to build and maintain, had safety problems, and created difficulties for other city functions, such as firefighting and utility maintenance. It consists of underground con- duits with insulated contact plates on top at the street surface. These plates are safely energized only when the contact shoe mounted under a BRT vehicle is directly overhead.
This ener- gization occurs when a powerful on-board magnet lifts up a continuous flexible power cable in a prefabricated, water- proof, and insulated box structure placed in a trench. This, in turn, energizes the contact plate at the street surface from underneath. Although this technology is not yet proven in extended revenue service, it has been successfully tested in Trieste, Italy. To date, speeds are limited to under about 33 kilometers 20 miles per hour. The strongest advantages of an all-electric vehicle using an external power source for BRT applications are environ- mental friendliness in terms of both noise and air at least in the vicinity of the line emissions and very high power and torque output, leading to high acceleration rates.
Modern elec- tric vehicles also feature much smoother acceleration and deceleration than conventional internal combustion vehicles with multi-shift point hydraulic-mechanical transmissions. Trolley buses generally also have the highest power-to- weight ratio of any transit vehicle, power that can be effec- tively transmitted to the pavement through high-traction rubber tires. A vehicle with electric propulsion will always have the potential for higher starting torque and higher horsepower at any given revolutions per minute RPMs than a thermal engine of equivalent physical size and weight.
An electric vehicle has excellent acceleration and hill climb ability because the maximum tractive effort the force applied at the wheel of a direct current motor occurs at 0 RPMs. By contrast, a diesel engine must spin to about 2, RPMs to produce maximum torque, and a clutch must be used to allow the engine to be engaged with the wheels at a standing start, at considerably lower RPMs and less starting torque.
Another advantage of electric traction is being able to power more than one set of wheels, which provides better traction in slippery conditions. As a practical matter, the greater torque at lower RPMs that is available with electric motors compared with thermal engines is a benefit with limited application. Normal acceler- ation rates generally will not exceed approximately 1. Otherwise, there will be excessive grip strength required of passengers, and they will be uncomfortable.
Electric traction allows high acceleration from a standing start, which is useful when there is frequent starting and stop- ping. However, this advantage fades as starting and stopping are less frequent and high speed is desired. When higher RPMs are maintained, either electric propulsion or internal combustion propulsion can achieve practical, maximum accel- eration rates.
A final advantage of electric vehicles is that because of their lower vibration, all systems including the electric motors, the air conditioning system, all electronics, and the body tend to have a longer service life than their thermal equivalents. The disadvantages of trolley buses are the expense of build- ing and maintaining them, visually intrusive infrastructure, and service inflexibility made necessary by the need to access power provided via costly and thus limited-extent fixed infra- structure such as overhead contact wires.
This inflexibility can be overcome in two ways. One way to overcome the service inflexibility of trolley buses is to use an all-electric vehicle for the all-stop service and LRT-like service in places where acceleration rate and environmental friendliness especially low noise are most important. Express or skip-stop services would be provided by vehicles with thermal engines that do not require access to overhead contact wires or another external energy source. Dual mode vehicles therefore have the advantages of both trolleys and normal buses with internal combustion engines.
The vehicles used in the Seattle CBD bus tunnel have this capacity. There can be two configurations for dual mode articu- lated vehicles. This is the most straightforward configuration, but it has drawbacks. It must carry two com- plete propulsion plants, making for a heavy vehicle. It also precludes the possibility of powering more than one axle simultaneously. This type of vehicle can also operate as either a trolley bus or a diesel-electric vehicle.
With this approach, the ride quality of the vehicle is significantly advanced because the all-electric drive eliminates the often harsh shift points associated with hydraulic-mechanical transmissions, but this type of vehicle tends to have lower fuel economy than other configurations. Having internally generated or externally provided via trol- ley wires electricity allows powering of multiple wheels in the same way as a light rail vehicle, an approach used for vehi- cles in Las Vegas; Nancy, France; and Boston as shown in Photo 6-O and currently in service in Lausanne, Switzerland.
When the motors are in the wheel, tires and wheels must be of a wide design. Putting the motors in the wheel hub is the approach taken in all of the specialized BRT vehicles and accounts for a sig- nificant portion of their much higher cost. One disadvantage is that these motors are very expensive, and the resulting system is heavy. Photo 6-P shows the drive axles with hub motors used on a BRT vehicle. Dual mode vehicles are attractive for transit operations because they can combine the performance and other environ- mental advantages of a trolley bus when they are needed with the freedom of movement of a conventional bus using an on-board prime mover.
The main disadvantages of dual mode vehicles are their weight and cost. Dual mode vehicles are also more complex than con- ventional buses. Whereas a conventional bus requires mainte- nance of a single thermal engine and a tried and true hydraulic- mechanical transmission, dual mode vehicles require more maintenance effort and cost because they have more compo- nents. True hybrid drive BRT vehicles perform even better than vehicles with a simple thermal-electric drive in which the thermal power is provided by diesel, liquid petroleum gas [LPG], or CNG without energy storage. Photo 6-Q shows a hybrid drive BRT vehicle.
A hybrid vehicle with energy storage allows an engine with less horsepower to be used because the engine can be run at a much more constant load. When high power is needed, the additional power is drawn from storage. Con- versely, the engine can recharge the energy storage medium while cruising or coasting. Regeneration during braking also recharges the storage medium and reduces brake wear and tear. There are noise and air pollution advantages to hybrid drive vehicles.
Peak noise levels are reduced since high engine RPMs are not required to achieve adequate acceleration or to climb hills. The air pollution and fuel consumption advan- tages stem from the more constant load on the engine. It is much easier to optimally tune an engine to reduce emissions and fuel consumption within a narrow range of operations than in a wide range of applications.
This is one of the spe- cial benefits of hybrid propulsion systems, even when diesel engines are part of the mix. Hybrid vehicles can use either of the two propulsion sys- tem configurations noted above under dual mode vehicles, but they may not need trolley wires. This approach, similar to the approach used by the Honda Insight and hybrid Honda Civic automobiles, is being tested in revenue service in Seattle as a replacement for its Breda dual mode vehicles. Fuel Cells Fuel cells, which are now in demonstration operation throughout the world, will mark a clear breakthrough in tech- nology for buses when commercialized, especially for BRT vehicles.
There are two basic fuel cell approaches for vehicles, one involving the use of hydro- gen gas carried in high-pressure cylinders up to bar pressure , and another in which the hydrogen is chemically separated from a liquid hydrocarbon fuel, such as methanol, in a reformer onboard the bus. Water vapor is the only exhaust product from a vehicle using pure hydrogen as a fuel, an improvement over the imperfectly combusted hydrocarbons, nitrous oxides, carbon monoxide and carbon dioxide that make up the potent greenhouse gas Photo Credit: Irisbus North America Photo 6-P.
Hybrid BRT vehicle.
IN ADDITION TO READING ONLINE, THIS TITLE IS AVAILABLE IN THESE FORMATS:
Fuel cell tech- nology promises to be an environmental boon for the transit industry as well as the entire large-vehicle industry because it can run on hydrogen created from a variety of renewable sources. Other than fan noise, fuel cell buses are remarkably quiet, quieter than most cars. This technology is still some years away from commer- cialization and competitive purchase price, but the special- ized vehicles have been designed for eventual conversion to fuel cell technology.
Both are frequently cited as reasons that BRT systems are often passed over in favor of LRT, and they are thus important vehicle planning and selection criteria. Air Emissions Great progress has been made in reducing air pollu- tion emissions from rubber-tired transit vehicles. The base diesel is significantly improved from previous generations of mechanically governed diesel engines.
Figures through illustrate that the propulsion technologies increasingly being found on specialized BRT vehicles and high-end conventional buses e. Diesel hybrids using low-sulphur fuels and continuously regenerating tech- nologies i. Clean diesels using low-sulphur fuel and catalytic convert- ers are not expected to cost significantly more to purchase when they go into more widespread use.
They will likely only cost a few cents more per mile to operate slightly higher fuel costs than current conventional diesel engines and have sim- ilar reliability levels. EPA has mandated that it be available everywhere by January Noise A study done in late s by Saab-Scania on bus noise determined that most bus noise was due to peculiarities asso- ciated with diesel engines that could be easily overcome.
Saab was able to reduce bus noise to levels that were the same or less than those of contemporary cars 78 decibels under full acceleration 10 meters from the vehicle on the curb-side. This was the situation over 20 years ago for previous- generation propulsion technology buses. Particulate emissions for various propulsion system types. Carbon monoxide emissions for various propulsion system types. The major conclusion here is that noise emissions can be reduced to levels that are, for all practical purposes, insignificant in most BRT applications, and planners and implementers should elect to put a noise emissions specifica- tion in their plans and procurement documents.
These systems, as distinct from the mechanical bus guidance technologies of the past e. The implications of such systems on right-of-way requirements, customer comfort, speeds, dwell times, and reliability can be profound. Rubber-tired, steered BRT vehicles can operate in any run- ning way environment, from running ways where they are mixed in with general traffic, to completely grade-separated, specialized busways like metro rail lines. This significant flexibility advantage allows a minimum of specialized guide- way to be built without forcing an undue amount of transfer-.
Ozone precursor emissions hydrocarbons, NOx for various propulsion system types. Fuel economy for various propulsion system types. These include the potential for passenger discomfort, the need for extra right-of-way with driven vehicles, and the difficulty drivers have in getting close enough to a station platform to permit no-step boarding and alighting. Perhaps the most significant disadvantage is the inability of conventional, steered-only vehicles buses to support rapid, no-step, station-platform-to-vehicle-floor boarding and alight- ing at low-platform stations that are easy and inexpensive to construct.
In response to these disadvantages, a number of technolo- gies have emerged in recent years that impart to BRT vehi- cles the kind of tracking precision normally associated with rail-based rapid-transit modes. Even low-floor buses may require stepping up and down if a vehicle is stopped far enough from the curb to require a step off the curb to the pavement level and then a step up into the vehicle.
These systems can provide the more comfortable tracking and minimum right-of-way require- ments of rail vehicles, but perhaps even more importantly, they allow no-step boarding and alighting, which reduces dwell time. This guidance approach, similar to that utilized on the rubber- tired, automated people mover systems often found at air- ports, has been proven in service for many years in Essen, Germany, and Adelaide, Australia, with newer, similar non-O-Bahn applications in a number of British cites e.
The guideway tapers where the vehicle enters the guided section to allow easy entrance. Once on the guideway, the operator does not steer, but applies only power and braking. After leaving the guideway, driver steering is reactivated. In Essen, the vehicles shared a tunnel with light rail vehicles. Both Essen and Adelaide applications operated successfully for years Essen has now ceased oper- ation with enviable safety records, few safety problems, and excellent customer satisfaction.
A more recent lateral mechanical guidance technique is to use one central guide rail or central metal guide groove in the roadway. In the guide rail approach, the rail is contacted by a guide wheel, or sheave. There is one sheave mounted between each set of wheels. In the guide groove approach, the guide is contacted by a wheeled arm mounted on the center- line of the bus.
In either case, the contacting mechanism can be retracted when the bus is not operated on a guided section. There are some differences in how this guidance approach has been utilized in specialized BRT vehicles. For example, on several vehicles, all axles swivel to provide all-wheel steering to simplify precision docking and reduce the turning radius. Another vehicle has rigid axles directly under the articulation joint, also permitting all wheels to swivel and fol- low the same track.
Both types of vehicles were tested extensively in revenue service on the Trans Val de Marne site in suburban Paris Ventejol, The advantages of mechanical guidance systems are their tight running trajectory; precision docking; and high degree of safety, simplicity, and robustness under severe operating conditions.
Disadvantages include vehicle weight and the additional infrastructure necessary for them to work e. It also may be difficult for vehicles to leave and enter guided track sections, precluding complex routing patterns. Guided vehicles often need a right-of-way that is physi- cally separate from other traffic because with some systems e. Photo 6-S illustrates a running way with guidance track used by mechan- ically guided vehicles in Nancy, France. Photo 6-T shows a running way used by the mechanically guided O-Bahn sys- tem in Adelaide, Australia. This photo illustrates the use of vertical curbs against which the guidance wheels play.
Optical Guidance Another lateral guidance technique uses a video camera mounted on the dashboard of the vehicle for position data acquisition. Guidance mechanism on BRT vehicle and trackway. It also allows vehicles to stop at stations within tight lateral tolerances. Optical guidance systems avoid the vehicle weight asso- ciated with mechanical systems, and infrastructure costs are modest because no physical guide is installed in the road beyond painted stripes.
With optical guidance sys- tems, the operator can take over at any time. Further, these systems are compatible with operating plans that feature mixed local and express operations on a single guideway because of their ease of driver-steered vehicle entry and exit. Optical guidance systems are used on some specialized BRT vehicles. As shown in Photo 6-U, the video camera on the dashboard and the painted dashed lines on the pave- ment are key components of the optical guidance system.
Photo 6-T. Running way with vertical guidance walls used by mechanically guided O-Bahn system Adelaide, Australia. BRT vehicle with a video camera on the vehicle dashboard and painted, dashed lines on the pavement as key components of the optical guidance system. The video systems work even if the painted guide lines are partially obscured by another vehicle, leaves, or snow. This is the case with most tracked BRT vehicle systems.
Optical guidance also lacks the safety of positive physical guidance. At high speeds, it is recommended that security curbs about 20 centimeters 8 inches high be used that backup guide wheels can follow in case of system failure. Other safety issues include snow obscuring the guidance lines and vandals painting errant ones.
The advantage of these systems is their lower cost and vehicle weight in comparison with mechanical systems and the fact that data can be acquired from the magnetic field with regard to snow cover or other pavement surface conditions. However, these systems cost more to install and maintain than optical systems. All guidance systems utilized for BRT, to date, provide lat- eral guidance that can always be overridden by the driver.
A driver must be present on every vehicle to start, accelerate, and stop it. Systems that provide longitudinal control e. Adaptive cruise control systems that automatically apply the brakes and release the accelerator if an obstruction a stopped vehicle is detected in front of the vehicle are already in use in trucks and will be adapted for BRT vehicle use.
The matched characteristics of the vehicle and phys- ical infrastructure also project a physical image. This image is further enhanced by any particular features and amenities unique to the service, such as precision docking and real-time information at stations. As described more fully in Chapter 8, the image of a BRT system should be carefully cultivated in the initial conceptual planning and design stages. This image may be necessary to the ultimate success of the sys- tem for a variety of reasons.
The other reason for cultivating a distinct image and identity is to use the system itself for advertising and conveying information about rout- ing and schedules. Seeing distinct vehicles on certain routes serving certain stops and stations conveys information about where and when the system goes. It is not always necessary to have a rail-like appearance to be successful, as some successful applications have shown.
The livery can be different from other buses, but match the livery at BRT stops, stations, and terminals, as well as on information signs, graphics, and all printed matter. Photo 6-W shows the As of , at least five European bus manufacturers Irisbus Civis, Bombardier, Neoplan, APTS, and Translohr have designed and built specialized BRT vehicles that are similar to light rail vehicles in appearance, interior, and other features such as guidance. Examples of the features of BRT vehicles include their large sizes and distinct shapes lengths from BRT running way with dashed lines for optical guidance system Rouen, France.
South American specialized vehicles resemble conventional buses much more in appearance, although there are significant functional differences e. In South America, the emphasis is more on acquisition cost and functionality than on image. Photo 6-X shows an meter foot dual mode track-guided modular BRT vehicle. Photo 6-Y shows a meter foot hybrid, which is a magnetically guided, modular BRT vehicle.
Photo 6-Z shows a The interior appearance of a vehicle should also be stylish, in keeping with the exterior appearance. Panoramic and curv- ing windows make the task of designing well-lit and attrac- tive interiors easier. Comfortable, upholstered seats with a generous pitch also contribute to a positive image.
However, functionality cannot take second place to appearance, even if specialized vehicles are selected. Easy and rapid passenger boarding, alighting, and circu- lation are still basic BRT vehicle requirements to minimize dwell times. These aid boarding, alighting, and circulation and also function as storage areas for baby carriages, strollers, shop- ping carts, and wheelchairs and, in the process, support the image of a quality system that meets the needs of the entire community.
All transit buses in the United States are being delivered with features to comply with the letter and spirit of the ADA.